Disk drive having a reinforcing arrangement against an external stress applied thereto

ABSTRACT

In a disk drive for using a disk cartridge including a magnetic disk, a reinforcing arrangement is coupled to a main frame, a main board, and a disk receiving/ejecting mechanism which is for receiving and ejecting the disk cartridge. The reinforcing arrangement resists an external stress, applied between the main frame and a cover opposite to the main frame, to protect a head assembly which is movable between the man frame and the cover in a radial direction of the magnetic disk. The main board and the disk receiving/ejecting mechanism are placed between the main frame and the cover and is coupled to the main frame.

BACKGROUND OF THE INVENTION

[0001] This invention relates to a thin-profile disk drive for use inrecording and reproducing information to and from a flexible disk (FD)as a magnetic recording medium.

[0002] As well known, a flexible disk drive (FDD) is for recording andreproducing information to and from a flexible magnetic disk as amagnetic recording medium. The magnetic disk is contained in a plasticcase. A combination of the magnetic disk and the plastic case isgenerally called a disk cartridge.

[0003] Such a disk drive comprises a main frame and a cover attachedopposite to the main frame. In order to recording or reproducing theinformation, the disk cartridge is set or inserted between the mainframe and the cover and held on a disk table provided in the disk drive.The disk table has a rotation shaft in the manner such that the centerof the magnetic disk is coincident with the rotation shaft of the disktable.

[0004] The disk table is supported on a main frame is driven and rotatedby a spindle motor which is mounted on a motor frame. The spindle motoris for rotating the magnetic disk included in the disk cartridge. Thedisk drive further comprises a pair of magnetic heads, i.e., upper andlower magnetic heads, for reading/writing data to/from the magnetic diskin the disk cartridge. The upper magnetic head is supported by a headassembly at its end. The head assembly is located on a rear side of thedisk drive and comprises upper and lower head supporting memberssupporting the upper and the lower magnetic heads, respectively. Thehead assembly is disposed above a principal surface of the main frameand spaced from the main frame. The head assembly supports the uppermagnetic head at its end so that the upper magnetic head is movable in apredetermined radial direction with respect to the magnetic disk.

[0005] The disk drive is often subjected to an external stress appliedbetween the main frame and the cover. For example, when the disk driveis strongly held by a user's hand before the disk cartridge is insertedtherein, at least one of the main frame and the cover is bent. As aresult, it is assumed that the disk drive is deformed. The deformationof the disk drive or other components due to the external stress causesa displacement of the head assembly. When the disk cartridge is insertedinto the disk drive in this condition, the magnetic heads may be damagedby the disk cartridge.

SUMMARY OF THE INVENTION

[0006] It is therefore an object of this invention to provide a diskdrive capable of preventing a magnetic head from being damaged even uponoccurrence of deformation of the disk drive.

[0007] Other objects of the present invention will become clear as thedescription proceeds.

[0008] According to this invention, there is provided a disk drive forusing a disk cartridge including a magnetic disk, the disk drivecomprising a main frame, a cover opposite to the main frame, a mainboard placed between the main frame and the cover and fixed to the mainframe, a disk receiving/ejecting mechanism placed between the main frameand the cover and coupled to the main frame for receiving and ejectingthe disk cartridge, a head assembly placed between the main frame andthe cover and movable in a radial direction of the magnetic disk, and areinforcing arrangement coupled to the main frame, the main board, andthe disk receiving/ejecting mechanism for resisting an external stress,applied between the main frame and the cover, to protect the headassembly.

BRIEF DESCRIPTION OF THE DRAWING

[0009]FIG. 1 is a plan view of an existing disk drive;

[0010]FIG. 2 is a plan view of the disk drive illustrated in FIG. 1 whena disk cartridge is being inserted;

[0011]FIG. 3 is a plan view of the disk drive illustrated in FIG. 1 whenthe disk cartridge is completely inserted;

[0012]FIG. 4 is a plan view showing a disk holder assembly used in thedisk drive illustrated in FIG. 1;

[0013]FIGS. 5A, 5B, and 5C are a plan view, a right side view, and arear view of an eject lever used in the disk drive illustrated in FIG.1;

[0014]FIG. 6 is a plan view of a disk drive according to an embodimentof this invention in the state where a cover is removed;

[0015]FIG. 7 is an exploded perspective view of the disk driveillustrated in FIG. 6;

[0016]FIG. 8 is a plan view of a characteristic part of the disk driveillustrated in FIG. 6; and

[0017]FIG. 9 is an exploded perspective view of the characteristic partof the disk drive illustrated in FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0018] In order to facilitate an understanding of this invention, anexisting flexible disk drive (FDD) will at first be described withreference to the drawing.

[0019] Referring to FIGS. 1 through 3, the existing flexible disk driveof a 3.5-inch type is adapted to drive a flexible magnetic disk of a3.5-inch type. In FIG. 1, a disk cartridge 140 illustrated in FIG. 2 isnot inserted. In FIG. 2, the disk cartridge 140 is being inserted. InFIG. 3, the disk cartridge 140 is completely inserted. In each of FIGS.1 through 3, an upper cover (not shown) is removed.

[0020] The disk cartridge 140 contains a flexible magnetic disk as amagnetic recording medium. The disk cartridge 140 is inserted into thedisk drive in an inserting direction depicted by an arrow A in FIGS. 1through 3. The disk cartridge 140 inserted into the disk drive is heldon a disk table 111 in the manner such that the center of the magneticdisk is coincident with a rotation shaft 111 a of the disk table 111.The disk table 111 is rotatably supported on an upper surface of a motorframe (not shown) attached to a main frame 113. The rotation shaft 111 ahas an axial direction (perpendicular to a drawing sheet) parallel to athickness direction of the main frame 113.

[0021] The disk table 111 is driven and rotated by a spindle motor 135disposed on the motor frame so that the magnetic disk in the diskcartridge 140 is rotated. A main board 130 with a number of electroniccomponents mounted thereon is attached to the main frame 113 and themotor frame.

[0022] The disk drive comprises a pair of magnetic heads, i.e., upperand lower magnetic heads for reading/writing data to/from the magneticdisk in the disk cartridge 140. In the figures, only the upper magnetichead 114 is illustrated.

[0023] The upper magnetic head 114 is supported by a head assembly 115at its end. The head assembly 115 is located on a rear side of the diskdrive. The head assembly 115 comprises an upper head supporting member115 a supporting the upper magnetic head 114 and a lower head supportingmember (not shown) supporting the lower magnetic head.

[0024] The head assembly 115 is disposed above a principal surface ofthe main frame 113 and spaced from the main frame 113, as will later bedescribed. The head assembly 115 supports the upper magnetic head 114 atits end so that the upper magnetic head 114 is movable in apredetermined radial direction (depicted by an arrow B in FIGS. 1through 3) with respect to the magnetic disk.

[0025] The main frame 113 has a rear wall 131 with a stepping motor 116fixed thereto. The stepping motor 116 serves to linearly drive the headassembly 115 in the predetermined radial direction B. More in detail,the stepping motor 116 has a rotation shaft (driving shaft) 161extending in parallel to the predetermined radial direction B. Therotation shaft 161 is provided with a male thread or external thread.The rotation shaft 161 has a forward end inserted through a hole formedin a support member 131 attached to the principal surface of the mainframe 113. The rotation shaft 161 is limited in position to extend inparallel to the predetermined radial direction B and the forward end ofthe rotation shaft 161 is rotatably held.

[0026] On the other hand, the head assembly 115 has an arm 151 extendingfrom the lower head supporting member to the rotation shaft 161. The arm151 has a forward end engaged with a root of the male thread formed onan outer peripheral surface of the rotation shaft 161. Therefore, whenthe rotation shaft 161 is rotated, the forward end of the arm 151 ismoved along the root of the male thread of the rotation shaft 161 sothat the head assembly 115 itself is moved in the predetermined radialdirection B. Thus, the stepping motor 116 serves as a drivingarrangement for linearly moving the head assembly 115 in thepredetermined radial direction B.

[0027] The rotation shaft 161 is disposed on one side of the headassembly 115. Therefore, the one side of the head assembly 115 ismovably supported by the rotation shaft 161 and spaced from theprincipal surface of the main frame 113.

[0028] However, by the rotation shaft 161 alone, it is impossible tosupport a whole of the head assembly 115 with a space kept from theprincipal surface of the main frame 113. Therefore, the head assembly115 is supported and guided by a guide bar (not shown) on the other sideof the head assembly 115.

[0029] Specifically, the guide bar is arranged on the other side of thehead assembly 115 opposite to the rotation shaft 161. The guide barextends in parallel to the predetermined radial direction B and has oneend and the other end fixed to the principal surface of the main frame113 as will later be described. The guide bar serves to guide the headassembly 115 in the predetermined radial direction B. Thus, the headassembly 115 as a whole is supported with a space kept from theprincipal surface of the main frame 113.

[0030] A flexible printed circuit (FPC) (not shown) extends from thehead assembly 115 towards the guide bar. The FPC is electricallyconnected to the main board 130 attached to the principal surface of themain frame 113.

[0031] The lower head supporting member of the head assembly 115 alsoserves as a supporting frame supporting the head assembly 115 so thatthe head assembly 115 is slidable along the guide bar. The lower headsupporting member has a protruding portion (not shown) protrudingtowards the guide bar. The guide bar is slidably fitted into theprotruding portion.

[0032] The disk drive further comprises an elect plate 121 and a diskholder 122. Each of the main frame 113, the elect plate 121, and thedisk holder 122 is formed by punching, pressing, and bending a metalplate.

[0033] The elect plate 121 is mounted on the main frame 113 to beslidable in the inserting direction A and an ejecting direction oppositethereto, i.e., to be slidable in a back-and-forth direction.

[0034] The disk holder 122 is disposed under the elect plate 121. Asillustrated in FIG. 4, the disk holder 122 has a principal surface 220and a pair of side walls 221 formed on opposite sides of the principalsurface 220 and faced to each other. The side walls 221 have a pair ofpins 222 and 223, respectively.

[0035] The disk holder 122 has a generally rectangular opening 224formed in a center area inward in the inserting direction A.Specifically, the opening 224 is formed at a position corresponding tothe upper head supporting member 115 a and extends in the predeterminedradial direction B. The opening 224 is surrounded by a generallyU-shaped ridge 225 rising upward from the principal surface 220.

[0036] On the other hand, the head assembly 115 comprises a pair of sidearms 153 (see FIGS. 1 through 3) extending in a lateral direction. Theside arms 153 are located on or above the ridge 225. In the state wherethe disk cartridge 140 is ejected from the disk holder 122, the sidearms 153 are engaged with the ridge 225 so that the upper magnetic head114 and the lower magnetic head are separated from each other.Furthermore, the disk holder 122 has another opening 226 formed at aright-hand side of the opening 224 inward in the insertion direction A.The opening 226 has a shape such that the rotation of a lever part of aneject lever (which will later be described) 125 is allowed.

[0037] The principal surface of the main frame 113 is covered with a subframe 123. The sub frame 123 has four corners fixed to the main frame113 by screws 231. Between the sub frame 123 and the eject plate 121,eject springs 124 are bridged. On the main frame 113, the eject lever125 is rotatably arranged in the vicinity of the head assembly 115.

[0038] Referring to FIGS. 5A through 5C, the eject lever 125 will bedescribed. The main frame 113 is provided with a rod pin (not shown)standing from the principal surface thereof and extending upward from apredetermined position on the right side and the rear side. The ejectlever 125 comprises a cylindrical part 250 to receive the rod pin fittedthereto, an arm part (lever part) 251 extending from the cylindricalpart 250 in a radial direction, a protruding part 252 formed on the armpart 251 and extending upward, and an arc-shaped locking part 253extending from a free end of the arm part 251 in a circumferentialdirection.

[0039] The eject lever 125 is provided with an eject lever spring (notshown) attached around the cylindrical part 250. The eject lever springurges the eject lever 125 in a counterclockwise direction in the figure.

[0040] The protruding part 252 is engaged with a forward end of the diskcartridge 140 to control a sliding movement of the eject plate 121 inthe back-and-forth direction.

[0041] The eject lever 125 has a tongue part 254 extending in parallelto the arm part 251 towards the spindle motor 116. The tongue part 254has a forward end 254 a expanding upward. The forward end 254 a servesto prevent the disk cartridge 140 from colliding with the lower magnetichead when the disk cartridge 140 is inserted into the disk drive.

[0042] The protruding part 252 has a protrusion 252 a protruding furtherupward to be engaged with a hook portion 261 a of a disk shutter arm 126which will later be described.

[0043] The eject lever 125 further has a stopper part 255. The stopperpart 255 is adapted to be engaged with the disk shutter arm 126 (whichwill later be described) to prevent the disk shutter arm 126 fromreturning to its initial position when the disk cartridge 140 iscompletely received in the disk drive.

[0044] On a right upper corner of the disk holder 122, the disk shutterarm 126 is attached to be rotatable around an arm pin 260. The diskshutter arm 126 has an arm part (lever part) 261 extending from theright upper corner in the radial direction, and an arm bushing 262formed at an end of the arm part 261 and extending downward.

[0045] The arm part 261 has the hook portion 261 a engaged with theprotrusion 252 a. As illustrated in FIG. 4, the arm bushing 262 isloosely fitted to the opening 226.

[0046] The arm bushing 262 has an end portion 262 a. The end portion 262a is engaged with a right upper edge of a shutter of the disk cartridge140 to controllably open and close the shutter. The arm bushing 262further has a protruding portion 262 b. The protruding portion 262 isengaged with the stopper part 255 when the disk cartridge 140 iscompletely received in the disk drive.

[0047] The disk shutter arm 126 is urged by a shutter arm spring 263 inthe counterclockwise direction.

[0048] Specifically, the shutter arm spring 263 is bridged between thearm part 261 and the disk holder 22. To the ridge 225, an upper magnetichead guard 132 is attached to protect the upper magnetic head 114 sothat the disk cartridge 140 does not collide with the upper magnetichead 114 when it is inserted into the disk drive.

[0049] The disk holder 122 is provided with a reverse insertionpreventing spring (not shown) attached to the right side of theprincipal surface 220 thereof. A combination of the disk holder 122, thedisk shutter arm 126, the arm pin 260, the upper magnetic head guard132, the reverse insertion preventing spring, and the disk shutter arm126 forms a disk holder assembly.

[0050] The main frame 113 has a front end portion provided with a frontpanel 127 attached thereto. The front panel 127 has an opening (notshown) allowing passage of the disk cartridge 140 and a door (not shown)for closing the opening. The front panel 127 is provided with an ejectbutton 128 protruding therefrom to be movable backward and forward. Theeject button 128 is fitted to a protruding part (not shown) formed at afront end of the elect plate 121 to protrude forward.

[0051] With the above-mentioned structure, the hook portion 261 a isengaged with the protrusion 252 a as illustrated in FIG. 1 to limit therotation of the eject lever 125 when the disk cartridge 140 is notinserted into the disk drive. Thus, the eject lever 125 is preventedfrom being rotated over a predetermined rotation angle unless the diskcartridge 140 is inserted into the disk drive.

[0052] Next, description will be made of an operation of inserting thedisk cartridge 140 into the disk cartridge and an operation of ejectingthe disk cartridge 140 inserted in the disk drive.

[0053] Before the disk cartridge 140 is inserted into the disk drive,the eject lever 125 and the disk shutter arm 126 are located atpositions illustrated in FIGS. 1 and 5. Specifically, the protrusion 252a is engaged with the hook portion 261 a. In this state, a stopper part255 of the eject plate 121 is engaged with the locking part 253.

[0054] In this state, the pins 222 and 223 are located at upperpositions in side walls 221 is located at an elevated position such thatthe disk cartridge 140 is acceptable. In this state, the side arms 153are engaged with the ridge 225 and the upper magnetic head 114 islocated at an upper position and separated from the lower magnetic head.

[0055] In this state, a user holds the disk cartridge 140 with itsforward end in contact with the door of the front panel 127 and insertsthe disk cartridge 140 in a normal state into the disk drive in theinserting direction A, as illustrated in FIG. 2. Then, as illustrated inFIG. 2, the shutter of the disk cartridge 140 is engaged with the endportion 262 a. After this time instant (this position), the diskcartridge 140 is further pushed inward against the urging force of theshutter arm spring 263 attached to the disk shutter arm 126. Then, thearm bushing 262 rotates in the opening 226 in the clockwise directiondepicted by an arrow D in FIG. 4. Following the rotation of the armbushing 262, the shutter of the disk cartridge 140 slides against theurging force of the shutter arm spring 263. As a consequence, theopening 226 is gradually exposed.

[0056] Immediately before the shutter of the disk cartridge 140 issufficiently opened by the disk shutter arm 126 and the disk cartridge140 is completely received in the disk drive, the forward end of thedisk cartridge 140 is engaged with the protruding part 252. At thistime, the protrusion 252 a is disengaged from the hook portion 261 a.Therefore, the eject lever 125 is rotatable in the clockwise direction.

[0057] When the disk cartridge is further pushed inward in the diskdrive, the eject lever 125 is rotated against the eject lever springattached thereto. As a consequence, the locking part 253 is disengagedfrom the stopper part 212. Therefore, the eject plate 121 is slightlyslides forward (reverse to the inserting direction A). This is becausethe eject plate 121 is urged forward by the eject spring 124.

[0058] On the other hand, the disk holder 122 is moved downward by theforward movement of the eject plate 121. This is because the pins 222and 223 formed on the side walls 221 are inserted into the cam portionsformed on side walls of the eject plate 121.

[0059] In the above-mentioned manner, the side arms 153 are disengagedfrom the ridge 225 and the upper head supporting member 115 a is moveddownward. As a consequence, the magnetic disk in the disk cartridge 140is clamped by the upper magnetic head 114 formed at the end of the headassembly 115 and the lower magnetic head. At this time, the protrudingportion 262 b is engaged with the stopper part 255 so that the diskshutter arm 126 is prevented from returning to its initial position.Since the eject plate 121 slightly slides forward, the eject button 128slightly protrudes forward from the front panel 127. This state isillustrated in FIG. 3. Thereafter, data can be read and written from andto the magnetic disk in the disk cartridge 140 by at least one of theupper magnetic head 114 and the lower magnetic head. Next, descriptionwill be made of the operation of ejecting the disk cartridge 140received in the disk drive. In this case, the user presses the ejectbutton 128 rearward in the inserting direction A. As a consequence, theeject plate 121 slides on the main frame 113 rearward in the insertingdirection A. Simultaneously, the pins 222 and 223 move along the camportions of the eject plate 121 so that the disk holder 122 is elevated.As a consequence, the side arms 153 are engaged with the ridge 225. Theupper magnetic head 114 supported at the end of the head assembly 115and the lower magnetic head are separated from the magnetic disk in thedisk cartridge 140. When the eject button 128 is further pushed rearwardin the inserting direction A, the disk holder 122 is located at apredetermined upper position and the eject lever 125 is rotated in thecounterclockwise direction due to the urging force of the eject leverspring.

[0060] Simultaneously, the stopper part 255 is disengaged from theprotruding portion 262 b. Due to the urging force of the shutter armspring 263, the disk shutter arm 126 is rotated in the counterclockwisedirection reverse to the direction depicted by the arrow D in FIG. 4. Asa consequence, the disk cartridge 140 received in the disk holder 122 ispushed out in the ejecting direction opposite to the inserting directionA so that the disk cartridge 140 is ejected from the disk drive. In thisstate, the locking part 253 is engaged with the stopper part 212 so thatthe eject plate 121 is prevented from moving towards the front panel127.

[0061] A cover (not shown) is attached to the main frame 113 andassembling is completed. The disk drive is often subjected to anexternal stress. For example, when the disk drive is held by a user'shand before the disk cartridge 140 is inserted therein, the cover ispressed and bent so that the disk drive is deformed.

[0062] However, those components other than the disk holder 122 issubjected to the external stress to be deformed. Therefore, thedeformation of the components due to the external stress is finallytransmitted to the disk holder 122. In this event, when the diskcartridge 140 is inserted into the disk drive, the upper magnetic head114 may be damaged.

[0063] Specifically, the upper magnetic head 114 lifted up by the diskholder 122 may be bent under the external stress to be drooped. In thisstate, the upper magnetic head 114 collides with the lower magnetichead. Therefore, the upper magnetic head 114 is damaged by mechanicalshock.

[0064] Now, description will be made of an embodiment of this invention.Similar parts will not be described in detail.

[0065] Referring to FIGS. 6 and 7, a disk drive 1 according to theembodiment of this invention comprises a main frame 11 provided with amain board 5 and a spindle motor 10.

[0066] Herein, a lower side in FIG. 6 is assumed to be a front side. Themain frame 11 has a flat base plate 11 a, a pair of side plates 11 b and11 c formed on opposite sides of the base plate 11 a to extend from thefront side to a rear side and standing up to be substantiallyperpendicular to the base plate 11 a, and a rear plate 11 d formed at arear end of the base plate 11 a and standing up to be substantiallyperpendicular to the base plate 11 a.

[0067] The main frame 11 is provided with a front bezel 16 formed at itsfront end. The front bezel 16 is rotatable around an upper end thereofbetween a closed position and an opened position and is urged by aspring 16 a to the closed position. The base plate 11 a is provided witha disk receiving/ejecting mechanism 20, a head assembly 30 movableforward and rearward, and a stepping motor 40 for moving and positioningthe head assembly 30.

[0068] The disk receiving/ejecting mechanism 20 comprises an eject plate21 and a disk holder 22 disposed inside the eject plate 21. A diskcartridge (see FIG. 2) containing a flexible magnetic disk is receivedin a space between the disk holder 22 and the base plate 11 a and on aturn table 13.

[0069] The eject plate 21 and the disk holder 22 are stacked to eachother. The eject plate 21 is urged frontward (downward in FIG. 6) by apair of coil springs 23 formed on opposite sides with respect to thedisk holder 22. The disk holder 22 is provided with an eject lever 25formed on one end face (right upper side in FIG. 6) thereof to berotatable around a shaft 25 a. Between the eject lever 25 and the diskholder 22, a coil spring 24 (corresponding to the shutter arm spring 263in FIG. 2) is bridged.

[0070] When the disk cartridge is received, one end of the diskcartridge is brought into contact with one end of the eject lever 25 torotate the eject lever 25 around the shaft 25 a in a clockwisedirection. At a predetermined position, the eject lever 25 is engagedwith the disk holder 22 to be stopped.

[0071] On the other hand, when the disk cartridge is ejected, an ejectbutton 21 a is pushed rearward (upward in FIG. 6). Then, the eject lever25 is disengaged from the disk holder 22 so that the eject lever 25 isrotated in a counterclockwise direction by a restoring force of the coilspring 24 to push out the disk cartridge.

[0072] As seen from FIG. 7, the disk drive 1 comprises a main portion50, a disk receiving/ejecting mechanism 20 received in the main portion50, and a cover 61 covering an upper side of the disk drive 1.

[0073] Referring to FIGS. 8 and 9, the main portion 50 comprises themain frame 11, the spindle motor 10 mounted on the base plate 11 a, andthe main board 5 mounted on the base plate 11 a in an area around thespindle motor 10.

[0074] The main board 5 has a generally L shape. The main board 5 isconnected to a flexible board 52 through a solder connecting portion 53.The main board 5 is provided with a plurality of electronic components 5b connected through a circuit pattern (not shown). The main board 5 isprovided with a connector 5 c mounted on its one end to carry outelectric connection with an external circuit. Screw holes 6′ is formedto fix the main board 5 to the base plate 11 a.

[0075] The base plate 11 a is provided with a head assembly 30 mountedon its one end. The head assembly 30 has one side inserted into a guiderail 18 and the other side engaged with an outer peripheral groove of adriving rod (screw rod) 41 a connected to a motor body 41 of thestepping motor 40.

[0076] On the rear side of the head assembly 30, a board 38 forelectrical connection is fastened to the main frame 11 by a screw 38 a.The stepping motor 40 is disposed on one side of the head assembly 30.The stepping motor 40 is positioned and fixed by fixing a support member43 via a screw 44.

[0077] On one side of the stepping motor 40, a small-sized circuit board42 is disposed to supply an electric current. The guide rail 18 is fixedby a fixing metal 17 to the base plate 11 a together with the main board5.

[0078] On the upper surface of the base plate 11 a, a lifting lever 46for lifting the disk cartridge in cooperation with the eject plate 21,the eject lever 25, and an unlock lever 47 for disengaging the diskholder 22 from the eject plate 21 are arranged.

[0079] Referring to FIG. 9, the main portion 50 is assembled in thefollowing manner. The main board 5 is fixed by screws 6 to the baseplate 11 a. The fixing metal 17 is attached by a screw 17 a to hold aninside of a rear end of the main board 5. The fixing metal 17 alsoserves to fix the guide rail 18.

[0080] Next, the flexible board 52 with a solenoid coil 55 is attachedto the base plate 11 a so that the center of the flexible board 52 iscoincident with a through hole 12 provided with a bearing 12 a. Abearing 14 is put on the center of the flexible board 52. A rotationshaft 13 a of the turn table 13 is rotatably inserted into the throughhole 12 through the bearing 12 a. The turn table 13 is attached so thatgrooves 13 b of the turn table 13 are coincident with cut-and-raisedportions 19 formed on the base plate 11 a. The turn table 13 isrotatable once it is attached. Unless the grooves 13 b are matched incircumferential position with the cut-and-raised portions 19, the turntable 13 is inhibited from being released upward.

[0081] As seen in a vertical section, the head assembly 30 has agenerally U shape and comprises an upper head supporting member 31 and alower head supporting member 34 faced to the upper head supportingmember 31 (see FIG. 9). An upper magnetic head (magnetic head element)33 is arranged inside the upper head supporting member 31. A lowermagnetic head (magnetic head element) is arranged inside the lower headsupporting member 34, although not shown in the figure.

[0082] On one side of the head assembly 30, the stepping motor 40 isdisposed. The stepping motor 40 has the driving rod 41 a protruding fromits one end. The driving rod 41 a has an outer peripheral groove 41 bengaged with one end of an arm 35 of the head assembly 30. The steppingmotor 40 is held by fixing the support member 43 by the screw 44 to aprotruding portion 45 of the base plate 11 a.

[0083] On the main board 5 exposed on the left side of the head assembly30, a standing member 48 made of a plastic material and having a S shapeas seen in a plan view is formed. The standing member 48 serves as aguide for a signaling flexible cable connected to the head assembly 30.A supporting part 43 a of the support member 43 and the standing member48 are substantially equal in height and stand up towards the cover 61.

[0084] The disk holder 22 has a generally rectangular opening 22 aformed in a center area inward in an inserting direction A along whichthe disk cartridge is inserted. Specifically, the opening 22 a is formedat a position corresponding to the upper head supporting member 31 andextends in a predetermined radial direction B. The opening 22 a issurrounded by a generally U-shaped ridge 22 b rising upward from theprincipal surface of the disk holder 22.

[0085] The disk holder 22 is provided with a cut-and-raised part 22 fformed frontward from the opening 22 a and rising from the principalsurface of the disk holder 22.

[0086] Each of the standing member 48, the supporting part 43 a, and thecut-and-raised part 22 f serves to maintain mechanical strength againstcompression in the vertical direction and serves as a reinforcing partresisting against deformation of the disk drive 1.

[0087] The supporting part 43 a is located rearward in the insertingdirection A and opposite to one side of the head assembly 30. Thestanding member 48 is located rearward in the inserting direction A andopposite to the other side of the head assembly 30.

[0088] On the other hand, the upper head supporting member 31 comprisesa pair of side arms 31 a extending in a lateral direction and a pair ofupper arms 31 b connected to the side arms 31 a, respectively. The sidearms 31 a are located on or above the ridge 22 b.

[0089] In the state where the disk cartridge is ejected from the diskholder 22, the side arms 31 a are engaged with the ridge 22 b so thatthe upper magnetic head 33 and the lower magnetic head are separatedfrom each other. Furthermore, the disk holder 22 has another opening 22c formed at a right-hand side of the opening 22 a inward in theinserting direction A. The opening 22 a has a shape such that therotation of a lever part of the eject lever 25.

[0090] The lifting lever 46 for lifting the disk cartridge incooperation with the eject plate 21 upon ejecting the disk cartridge isrotatably attached to the base plate 11 a by a pin 46 a. The unlocklever 47 for releasing the engagement between the disk holder and theeject plate 21 in the back-and-forth direction is rotatably attached tothe base plate 11 a by a pin 47 a. The main portion 50 illustrated inFIG. 8 is assembled in the manner illustrated in FIG. 9.

[0091] Furthermore, the disk receiving/ejecting mechanism 20 is receivedin the main portion 50 as illustrated in FIG. 7. Then, the structureillustrated in FIG. 6 is obtained. Furthermore, the cover 61 illustratedin FIG. 7 is attached and assembling of the disk drive 1 is completed.

[0092] The disk drive 1 thus completed may be subjected to an externalstress. For example, when the disk drive 1 is held by a user's handbefore the disk cartridge is inserted therein, the cover 61 is pressedand bent so that the disk drive 1 is deformed.

[0093] In this event, a combination of the standing member 48, thesupporting part 43 a, and the cut-and-raised part 22 f serves as areinforcing arrangement which is for resisting the deformation of thedisk drive 1 to protect the head assembly 30. it is to be noted that thestanding member 48, the supporting part 43 a, and the cut-and-raisedpart 22 f are placed at three corners of a triangle shape, respectively.When the deformation of the components due to the external stress isfinally transmitted to the disk holder 22, the cut-and-raised part 22 flifting the upper magnetic head 33 serves to correct the deformation.

[0094] Specifically, the upper magnetic head 33 and the disk holder 22are simultaneously deformed by the same amount when subjected to theexternal stress. Therefore, the upper magnetic head 33 located in theopening 22 a does not project beyond the ridge 22 b so that the uppermagnetic head 33 is not damaged or broken.

[0095] As described above, the disk holder 22 lifting the upper magnetichead 33 is provided with the cut-and-raised part 22 f as acountermeasure against the external stress. In the normal condition, theupper magnetic head 33 is accommodated in the opening 22 a. The uppermagnetic head 33 and the disk holder 22 are simultaneously deformed bythe same amount when subjected to the external stress. Therefore, theupper magnetic head 33 located inside the ridge 22 b does not projectbeyond the ridge 22 b so that the upper magnetic head 33 is preventedfrom being damaged.

What is claimed is:
 1. A disk drive for using a disk cartridge includinga magnetic disk, said disk drive comprising: a main frame; a coveropposite to said main frame; a main board placed between said main frameand said cover and fixed to said main frame; a disk receiving/ejectingmechanism placed between said main frame and said cover and coupled tosaid main frame for receiving and ejecting said disk cartridge; a headassembly placed between said main frame and said cover and movable in aradial direction of said magnetic disk; and a reinforcing arrangementcoupled to said main frame, said main board, and said diskreceiving/ejecting mechanism for resisting an external stress, appliedbetween said main frame and said cover, to protect said head assembly.2. A disk drive according to claim 1, wherein said diskreceiving/ejecting mechanism comprises: an eject plate coupled to saidmain frame for ejecting a disk cartridge; and a disk holder coupled tosaid eject plate for holding said disk cartridge, said reinforcingarrangement comprising: a supporting part connected to said main frameand standing up towards said cover; a standing member connected to saidmain board and standing up towards said cover; and a cut-and-raised partformed on said disk holder and standing up towards said cover.
 3. A diskdrive according to claim 2, wherein said supporting part, said standingmember, and said cut-and-raised part are placed at three corners of atriangle shape, respectively.
 4. A disk drive according to claim 2,wherein said supporting part is located rearward in an insertingdirection of said disk cartridge and faced to one side of said headassembly, said standing member being located rearward in the insertingdirection and faced to the other side of said head assembly, saidcut-and-raised part being located frontward in the inserting direction.5. A disk drive according to claim 2, further comprising a supportmember connected to said main frame, said supporting part being formedon said support member.
 6. A disk drive according to claim 5, furthercomprising a stepping motor supported by said support member for movingsaid head assembly in the radial direction, said supporting partsupporting a rotation shaft of said stepping motor.